Contact resistance test structure and method suitable for three-dimensional integrated circuits

ABSTRACT

A contact resistance test structure, a method for fabricating the contact resistance test structure and a method for measuring a contact resistance while using the contact resistance test structure are all predicated upon two parallel conductor lines (or multiples thereof) that are contacted by one perpendicular conductor line absent a via interposed there between. The test structure and related methods are applicable within the context of three-dimensional integrated circuits.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.12/699,206, filed Feb. 3, 2010, and claims the benefit of U.S.Provisional Patent Application Ser. No. 61/152,994 filed on Feb. 17,2009, the entire content and disclosure of which is incorporated hereinby reference.

BACKGROUND

1. Field of the Invention

The invention relates generally to microelectronic structures. Moreparticularly, the invention relates to contact resistance teststructures within microelectronic structures.

2. Description of the Related Art

As microelectronic structures and microelectronic devices have decreasedin aerial plan-view dimensions to a point where aerial linewidthdimensions are nearing physical limitations of metal oxide semiconductorfield effect transistor (MOSFET) scaling and lithographic capabilities,a trend has recently evolved within microelectronic fabrication, and inparticular within semiconductor fabrication, to utilize a third verticaldimension when fabricating microelectronic structures. The use of such athird vertical dimension provides three-dimensional integrated circuits.

Although such three-dimensional integrated circuits are desirable withinthe microelectronic fabrication and semiconductor fabrication arts, suchthree-dimensional integrated circuits are nonetheless not entirelywithout problems. In particular, it is desirable within suchthree-dimensional integrated circuits to assure that vertical electricalconnections to successively vertically layered structures areelectrically functional, and thus also have a desirably low contactresistance.

Contact resistance measurement structures that are applicable tothree-dimensional circuits are known in the microelectronic fabricationand semiconductor fabrication arts.

For example, Chen et al., in “Contact Resistance Measurement of BondedCopper Interconnects for Three-Dimensional Integration Technology,” IEEEElectron Device Letters 2004, Digital Object Identifier10.1109/LED.2003.821591, teaches a contact resistance test structure foruse within bonded copper interconnects within three-dimensionalintegrated circuits. This particular contact resistance test structurecomprises an overlapping X shaped test structure that is not susceptibleto misalignment.

As microelectronic technology, including semiconductor technology,continues to advance, the evolution of three-dimensional integratedcircuits is likely to continue to be prominent. Thus, desirable are teststructures and related methods, such as but not limited to contactresistance test structures and related methods, that provide forefficient and reliable integration of three-dimensional integratedcircuits.

SUMMARY

The invention provides a test structure for measuring a contactresistance within a three-dimensional integrated circuit, a method forfabricating the test structure for measuring the contact resistancewithin the three-dimensional integrated circuit and a method formeasuring a contact resistance within the three dimensional integratedcircuit while using the test structure. Each of the foregoing teststructure and related methods is predicated upon a plurality of parallelconductor lines being crossed by and contacted by a single nominallyperpendicular conductor line. By using the plurality of parallelconductor lines crossed by and contacted by the single perpendicularconductor line, this particular contact resistance test structurereadily provides for a more precise contact resistance measurement dueto an ability to consider parallel conductor line separation andperpendicular conductor line width dimensions when designing,fabricating and using the contact resistance test structure.

Within the embodiment and the invention, a “perpendicular” conductorline is intended to be perpendicular to the plurality of parallelconductor lines within the limitations of manufacturing tolerance, whichis generally from +5 to −5 degrees of perpendicular (or +5 to −5 degreesof parallel for the plurality of parallel conductor lines).

A particular contact resistance test structure in accordance with theinvention includes a substrate. The contact resistance test structurealso includes at least two parallel conductor lines located co-planarover the substrate. The contact resistance test structure also includesat least one perpendicular conductor line located perpendicular to,non-planar with and contacting the at least two parallel conductor linesabsent a via interposed between the perpendicular conductor line andeither of the two parallel conductor lines.

A particular method for fabricating a contact resistance test structurein accordance with the invention includes providing a first substrate.The method also includes forming at least two parallel conductor linesplanarized, exposed and embedded within a planarized dielectric layerover the first substrate. The method also includes providing a secondsubstrate. The method also includes forming at least one conductor lineplanarized, exposed and embedded within a planarized dielectric layerover the second substrate. The method also includes laminating the firstsubstrate and the second substrate so that the at least one conductorline over the second substrate perpendicularly crosses and contacts theat least two parallel conductor lines over the first substrate. Themethod also includes forming at least two conductor contacts through atleast one of the first substrate and the second substrate to the atleast two parallel conductor lines.

A particular method for measuring a contact resistance while using atest structure in accordance with the invention includes providing afirst contact resistance test structure that includes: (1) a substrate;(2) at least two parallel conductor lines having a first separation S1located co-planar over the substrate; and (3) at least one perpendicularconductor line having a first width W1 located perpendicular to,non-planar with and contacting the two parallel conductor lines absent avia interposed between the perpendicular conductor line and either ofthe two parallel conductor lines. The method also includes measuring afirst resistance R1 through the first contact resistance test structureby contact to the two parallel conductor lines.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features and advantages of the invention are understoodwithin the context of the Description of the Preferred Embodiment, asset forth below. The Description of the Preferred Embodiment isunderstood within the context of the accompanying drawings that form amaterial part of this disclosure, wherein:

FIG. 1A to FIG. 12 shows a series of schematic cross-sectional,plan-view and perspective-view diagrams illustrating the results ofprogressive process steps in fabricating a microelectronic structurethat comprises a three-dimensional integrated circuit that furtherincludes a contact resistance test structure in accordance with aparticular embodiment of the invention.

FIGS. 1A/B, 2A/B, 3A/B show first substrate etching when fabricating themicroelectronic structure.

FIGS. 4A/B show via formation with respect to FIGS. 1A/B, 2A/B, 3A.

FIGS. 5A/B, 6, 7A/B show first conductor structure formation withrespect to FIG. 4.

FIGS. 8A/B show second substrate etching with respect to FIGS. 5A/B, 6,7A/B.

FIGS. 9A/B show second conductor structure formation with respect toFIGS. 8A/B.

FIGS. 10A/B/C show lamination with respect to FIGS. 9A/B.

FIG. 11 shows contact pad formation with respect to FIGS. 10A/B/C.

FIG. 12 shows a final perspective-view of the contact resistance teststructure.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention, which includes a contact resistance test structure, amethod for fabricating the contact resistance test structure and amethod for using the contact resistance test structure, is understoodwithin the context of the description set forth below. The descriptionset forth below is understood within the context of the drawingsdescribed above. Since the drawings are intended for illustrativepurposes, the drawings are not necessarily drawn to scale.

FIG. 1A to FIG. 12 show a series of schematic cross-sectional, plan-viewand perspective-view diagrams illustrating the results of progressivestages in fabricating a contact resistance test structure within athree-dimensional integrated circuit structure (i.e., a microelectronicstructure) in accordance with a particular embodiment of the invention.This particular embodiment of the invention comprises a particular solepreferred embodiment of the invention.

FIG. 1A and FIG. 1B show a schematic cross-sectional diagram and aschematic plan-view diagram of the microelectronic structure at an earlystage in the fabrication thereof in accordance with this particular solepreferred embodiment.

FIG. 1 shows a first substrate 10. A first dielectric layer 12 islocated and formed upon the first substrate 10. A stop layer 14 (i.e.,intended as having etch stop properties, as well as planarizing stopproperties, in accordance with the disclosure below) is located andformed upon the first dielectric layer 12. A second dielectric layer 16is located and formed upon the stop layer 14. A first resist layer 18that defines a plurality of apertures A that expose the seconddielectric layer 16 is located and formed upon the second dielectriclayer 16.

Each of the foregoing first substrate 10 and overlying layers 12, 14, 16and 18 may comprise materials, have dimensions and be formed usingmethods that are otherwise generally conventional in the microelectronicfabrication art, including the semiconductor fabrication art.

For example, the first substrate 10 may comprise a material selectedfrom the group including but not limited to conductor materials,semiconductor materials and dielectric materials. More particularly, thefirst substrate 10 comprises a semiconductor substrate. Such asemiconductor substrate may comprise any of several semiconductormaterials. Non-limiting examples include silicon, germanium,silicon-germanium alloy, silicon-carbon alloy, silicon-germanium-carbonalloy and compound (i.e., III-V and II-VI) semiconductor materials.Non-limiting examples of compound semiconductor materials includegallium arsenide, indium arsenide and indium phosphide semiconductormaterials. Typically, the first substrate 10 comprises a semiconductorsubstrate that has a generally conventional thickness.

Each of the first dielectric layer 12 and the second dielectric layer 16may comprise any of several dielectric materials. Non-limiting examplesinclude oxides, nitrides and oxynitrides, particularly of silicon, butoxides, nitrides and oxynitrides of other elements are not excluded. Thefirst dielectric layer 12 and the second dielectric layer 16 maycomprise the same or different dielectric materials, and may be formedusing any of several methods. Non-limiting examples include ionimplantation methods, thermal or plasma oxidation or nitridationmethods, chemical vapor deposition methods and physical vapor depositionmethods. Typically, each of the first dielectric layer 12 and the seconddielectric layer 16 comprises a silicon oxide dielectric material formedto a thickness from 100 to 5000 nanometers.

The stop layer 14 typically comprises a hard mask material. In generalhard mask materials may be selected from the same group of dielectricmaterials as the first dielectric layer 12 and the second dielectriclayer 16. However, the stop layer 14 comprises a different material thanthe first dielectric layer 12 and the second dielectric layer 16 andthus the stop layer has a different relative etch rate characteristic incomparison with the first dielectric layer 12 and the second dielectriclayer 16. Thus, and without limitation, when the first dielectric layer12 and the second dielectric layer 16 comprise a silicon oxidedielectric material as is suggested above, the stop layer 14 typicallycomprises a silicon nitride material. Alternative materials combinationsfor the first dielectric layer 12, the stop layer 14 and the seconddielectric layer 16 are also contemplated within the context of theinstant embodiment. Typically, the stop layer 14 comprises such asilicon nitride material that has a thickness from 10 to 50 nanometers.

The first resist layer 18 may comprise any of several resist materials.Included in general are electron beam resist materials and photoresistmaterials. Also more particularly included are positive resistmaterials, negative resist materials and hybrid resist materials thathave properties of both positive resist materials and negative resistmaterials. Typically, the resist layer 18 comprises a positive resistmaterial or a negative resist material that has a thickness from 100 toabout 600 nanometers, and defines the apertures A that have a linewidthfrom about 0.2 to 10 micrometers.

FIG. 2A and FIG. 2B show the results of etching through the seconddielectric layer 16, the stop layer 14 and the first dielectric layer 12to form a corresponding second dielectric layer 16′, stop layer 14′ andfirst dielectric layer 12′ that expose the substrate 10 within aplurality of apertures A′, and while using the first resist layer 18 asan etch mask. FIG. 2A and FIG. 2B also show the results of subsequentlystripping the first resist layer 18 from the second dielectric layer 16′after having etched the apertures A′ through the second dielectric layer16, the stop layer 14 and the first dielectric layer 12.

The second dielectric layer 16, the stop layer 14 and the firstdielectric layer 12 may be etched to form the second dielectric layer16′; the stop layer 14′ and the first dielectric layer 12′ while usingthe first resist layer 18 as an etch mask layer, while using etchmethods and etch materials that are otherwise generally conventional inthe microelectronic fabrication art. Included in particular are wetchemical etch methods and materials, and dry plasma etch methods andmaterials. In accordance with this particular process step, as well assubsequent process steps within the context of this particularembodiment, dry plasma etch methods and materials are particularlydesirable insofar as dry plasma etch methods and materials provide forgenerally straight sidewalls of etched layers such as the seconddielectric layer 16′, the stop layer 14′ and the first dielectric layer12′.

In addition, the first resist layer 18 may be stripped from the seconddielectric layer 16′ while using methods and materials that are alsogenerally conventional in the microelectronic fabrication art. Includedin particular are wet chemical stripping methods and materials, dryplasma stripping methods and materials, and combinations of wet chemicalstripping methods and materials and dry plasma stripping methods andmaterials.

FIG. 3A and FIG. 3B first show the results of etching the substrate 10to form a substrate 10′ while using at least the stop layer 14′ and thefirst dielectric layer 12′ (and typically also the second dielectriclayer 16′) as an etch mask layer. FIG. 3A and FIG. 3B also show theresults of stripping the second dielectric layer 16′ from the stop layer14′. Whether the second dielectric layer 16′ is stripped before or afteretching the substrate 10 to form the substrate 10′, the seconddielectric layer 16′ may be stripped from the stop layer 14′ while inparticular using an anisotropic reactive ion etch method that does notprovide an undercut of the first dielectric layer 12′ with respect tothe stop layer 14′.

Within FIG. 3A and FIG. 3B, the particular etching of the substrate 10to form the substrate 10′ also generally uses an anisotropic etch methodthat provides generally straight sidewalls of a plurality of aperturesA″ that are now included within the substrate 10′.

FIG. 4A and FIG. 4B first shows liner layers 20 located and formedconformally into each of the plurality of apertures A″ that isillustrated in FIG. 3A, while not completely filling each of theapertures A″ that is illustrated in FIG. 3A. FIG. 4A and FIG. 4B alsoshow a plurality of first conductor layers 22 located and formed uponthe liner layers 20 and completely filling the apertures A″.

The liner layers 20 typically comprise a dielectric liner material. Thedielectric liner material will typically comprise a dielectric materialselected from the same group of dielectric materials as the firstdielectric layer 12′ but not the same dielectric material as the stoplayer 14′. Typically, the liner layers 20 are located and formedconformally incompletely filling the apertures A″, to a thickness from10 to 500 nanometers.

The first conductor layers 22 may comprise any of several conductormaterials, including, but not limited to certain metals, metal alloys,metal nitrides and metal silicides, as well as laminates thereof andcomposites thereof. The first conductor layers 22 may also comprisedoped polysilicon and polysilicon-germanium alloy materials (i.e.,having a dopant concentration from about 1e18 to about 1e22 dopant atomsper cubic centimeter) and polycide materials (doped polysilicon/metalsilicide stack materials). Similarly, the foregoing materials may alsobe formed using any of several methods. Non-limiting examples includesalicide methods, chemical vapor deposition methods and physical vapordeposition methods, such as, but not limited to evaporative methods andsputtering methods. Typically, the first conductor layers 22 comprise ametal conductor material, such as an aluminum, copper or tungsten metalconductor material, but most particularly a copper conductor material.Suitable barrier materials may also be included.

The liner layers 20 and the first conductor layers 22 are typicallyformed incident to a sequential blanket layer deposition and subsequentplanarization of a precursor layer to the liner layers 20 and aprecursor layer to the conductor layers 22. Particular planarizingmethods may include, but are not necessarily limited to mechanicalplanarizing methods and chemical mechanical polish planarizing methods.Chemical mechanical polish planarizing methods are generally preferred.

FIG. 5A and FIG. 5B illustrate a second resist layer 24 located andformed upon the stop layer 14′ and leaving exposed portions of the stoplayer 14′, as well as the liner layers 20 and the first conductor layers22.

The second resist layer 24 is otherwise analogous, equivalent oridentical to the first resist 18 that is illustrated in FIG. 1, butrather includes a pattern that includes parallel lines L as open spaces,where a central two of the parallel lines L as open spaces are connectedat one end by additional open space C.

FIG. 6 shows the results of transferring the second resist layer 24pattern into the stop layer 14′ to provide a stop layer 14″ that is notcompletely etched, while also etching the liner layers 20 and theconductor layers 22 to form corresponding liner layers 20′ and conductorlayers 22′. As is illustrated in FIG. 6, this particular etching is alsointended as an anisotropic etching.

FIG. 7A and FIG. 7B first show the results of stripping the secondresist layer 24 from the stop layer 14″ within the microelectronicstructure whose schematic cross-sectional diagram is illustrated in FIG.6. Such stripping of the second resist layer 24 from the stop layer 14″within the microelectronic structure of FIG. 6 to provide in part themicroelectronic structure of FIGS. 7A and 7B is otherwise analogous,equivalent or identical to the stripping of the first resist layer 18from the microelectronic structure of FIG. 1A and FIG. 1B in-part whenforming the microelectronic structure of FIGS. 2A and 2B.

FIG. 7A and FIG. 7B also show the results of forming and planarizing asecond conductor layer 26 into the recesses within the stop layer 14″,after having stripped the second resist layer 24 from the stop layer14″. The second conductor layer 26 may be formed using methods andmaterials analogous, equivalent or identical to the methods andmaterials that are used for forming the first conductor layer 22. Inparticular, such methods and materials include blanket layer depositionand planarizing methods that may be used to provide the second conductorlayers 26 formed of a conductor material, such as but not limited to ametal conductor material, further such as but not limited to analuminum, copper or tungsten conductor material, and most particularly acopper conductor material. Suitable barrier materials, such as but notlimited to tantalum and titanium, as well as nitrides of tantalum,titanium and tungsten, may also be used. The second conductor layer 26is intended to have a thickness from 0.100 to 10 micrometers, with eachof the parallel lined sections of the second conductor layer having alinewidth from 0.1 to about 10 micrometers.

FIG. 7A and FIG. 7B show a first substrate 10′ that is completelyfabricated and finished to provide a planarized surface that includes astop layer 14″ and four parallel conductor lines (a central two of whichare connected) within a second conductor layer 26 that is embeddedwithin the stop layer 14″.

FIG. 8A and FIG. 8B show the results of an early stage in fabrication ofa second substrate intended to be mated with the first substrate 10′that is illustrated in FIG. 7A and FIG. 7B to provide, at least in-part,a three-dimensional integrated circuit that includes a contactresistance test structure in accordance with the instant embodiment ofthe invention.

FIG. 8A and FIG. 8B show a second substrate 30. A third dielectric layer32 is located and formed upon the second substrate 30. A third resistlayer 34 is located and formed upon third dielectric layer 32.

Within the context of the microelectronic structures of FIG. 8A and FIG.8B, the substrate 30 that is illustrated within FIG. 8A may comprisematerials and have dimensions analogous, equivalent or identical to thesubstrate 10 that is illustrated in FIG. 1A. Typically, each of thesubstrate 10 that is illustrated in FIG. 1A and the substrate 30 that isillustrated in FIG. 8A includes a semiconductor substrate and moreparticularly a silicon semiconductor substrate.

Similarly, the third dielectric layer 32 may comprise dielectricmaterials, have dimensions and be formed using methods, analogous,equivalent or identical to the materials, dimensions and methods thatare used within the context of the first dielectric layer 12 and thesecond dielectric layer 16 that are illustrated in FIG. 1A. Finally, thethird resist 34 is otherwise generally analogous, equivalent oridentical to the second resist layer 24 that is illustrated in FIG. 5Aor FIG. 5B, or the first resist layer 18 that is illustrated in FIG. 1Aand FIG. 1B.

FIG. 8A also shows a plurality of apertures A′″ in-part within the thirddielectric layer 32, where aerial dimensions of the apertures A′″correspond with the third resist 34. Such a correspondence is intendedas indicative of etching a portion of the third dielectric layer 32while using the third resist 34 as an etch mask.

FIG. 9A and FIG. 9B first show the results of stripping the third resistlayer 34 from the third dielectric layer 32. Such stripping may beeffected using methods and materials that are described above withrespect to stripping the second resist layer 24 from the stop layer 14″and the first resist layer 18 from the second dielectric layer 16′.

FIG. 9A and FIG. 9B also show the results of forming and planarizing aplurality of third conductor layers 36 within the recesses within thethird dielectric layer 32. These particular third conductor layers 36may comprise materials, have dimensions and be formed using methodsanalogous, equivalent or identical to the materials, dimensions andmethods used within the context of the second conductor layers 26 thatare illustrated in FIG. 7A and FIG. 7B.

Preferably, the third conductor layers 36 comprise a copper conductormaterial, although neither the embodiment nor the invention isnecessarily so limited.

FIGS. 10A, 10B and 10C illustrate the results of laminating the embeddedconductor layer surfaces of the substrate 10′ that is illustrated inFIG. 7A and FIG. 7B with the substrate 30 that is illustrated in FIG. 9Aand FIG. 9B. As is illustrated in particular within FIG. 10B, the thirdconductor layer 36 contacts the second conductor layer 26 absent a viainterposed therebetween. The microelectronic structure of FIG. 7A andFIG. 7B may be laminated with the microelectronic structure of FIG. 9Aand FIG. 9B while using laminating methods that are otherwise generallyconventional in the microelectronic fabrication art for formingthree-dimensional integrated circuits. Included in particular arepressure laminating methods, ultrasonic laminating methods andthermosonic laminating methods. Typically, the three-dimensionalintegrated circuit of FIGS. 10A, 10B and 10C results from a thermal andpressure assisted bonding of the microelectronic structure of FIG. 7Aand FIG. 7B with the microelectronic structure of FIG. 9A and FIG. 9B ata temperature from 20 to 800 degrees centigrade and a pressure from 1 to5 atmospheres pressure.

FIG. 11 first shows the results of etching the substrate 10′ that isillustrated in FIG. 10C to provide a substrate 10″ that includesrecesses that leave exposed end portions of the liner layers 20′ and thefirst conductor layers 22′ opposite the ends thereof that contact thesecond conductor layers 26. Such etching of the substrate 10′ to providethe substrate 10″ that includes the recesses will typically include amasked etching of the substrate 10′ while using an etchant that isappropriate to the material from which is comprised the substrate 10′.

Also contemplated within the microelectronic structure of FIG. 11 isthat the substrate 10″ may also be thinned to in-part form the substrate10″. Such thinning may be effected using methods that are conventionalin the microelectronic fabrication art. Included in particular, but alsonot limiting, are mechanical planarizing methods and chemical mechanicalpolish planarizing methods. Chemical mechanical polish planarizingmethods are generally more common.

FIG. 11 also shows a plurality of fourth conductor layers 28 (i.e.,contact pads) located and formed contacting the first conductor layers22′. The fourth conductor layers 28 may comprise materials and be formedusing methods analogous, equivalent or identical with the thirdconductor layers 36, the second conductor layers 26 and the firstconductor layers 22′.

FIG. 12 shows a perspective-view diagram illustrating the disposition offirst, second, third and fourth conductor layers 22′, 26, 36 and 28within the contact resistance test structure of the instant embodiment.FIG. 12 illustrates the fourth conductor layer 28 contact pads locatedconnected to and contacting the first conductor layers 22′ that formtest structure vias to which contact may be directly made incident toin-line testing. FIG. 12 also shows the second conductor layers 26 thatcontact the first conductor layers 22′ and the third conductor layers 36that contact the second conductor layers 26 perpendicularly.

This particular embodiment also contemplates that a width W of a thirdconductor layers 36 may be varied to provide a first width W1 and asecond width W2, and as well a separation distance S between adjacentsecond conductor layers 26 may also be varied to provide a first spacingS1 and a second spacing S2. One may then obtain three resistancemeasurements of the contact resistance test structure of the instantembodiment as follows: R1 at W1 and S1; R2 at W1 and S2; and R3 at W2and S1.

Further:

R1=n(Rb+2Rc)+Rt

R2=n(RbS2/S1+2Rc)+Rt

R3=n(Rb+2Rc)W1/W2+Rt

where:n=number of third conductor layers 36Rb=resistance of third conductor layer 36 between a pair of secondconductor layers 26Rc=contact resistance for a second conductor layer 26 and a thirdconductor layer 36Rt=measured test structure resistance in a measured test structure chainthat includes other than just Rb and Rc. In practice, Rt is keptconstant for different measured test structure chains so that the valuesof (R2−R3) and (R1−R2) are independent with respect to Rt.

Thus:

Rc=[R2−R3−(R1−R2)(b−a)/a]/2nb

Where:

a=1−S2/S1b=1−W1/W2

Therefore:

if a=b=½; then Rc=(R2−R3)/n

The preferred embodiment and example of the invention are illustrativeof the invention rather than limiting of the invention. Revisions andmodifications may be made to methods, materials, structures anddimensions of a contact resistance test structure in accordance with thepreferred embodiment and example, while still providing a contactresistance test structure, a method for fabrication thereof and a methodfor use thereof in accordance with the invention, further in accordancewith the accompanying claims.

What is claimed is:
 1. A method for fabricating a contact resistancetest structure comprising: providing a first substrate; forming at leasttwo parallel conductor lines planarized, exposed and embedded within aplanarized dielectric layer over the first substrate; providing a secondsubstrate; forming at least one conductor line planarized, exposed andembedded within a planarized dielectric layer over the second substrate;laminating the first substrate and the second substrate so that the atleast one conductor line over the second substrate perpendicularlycrosses and contacts the at least two parallel conductor lines over thefirst substrate; and forming at least two conductor contacts through oneof the first substrate and the second substrate to the at least twoparallel conductor lines.
 2. The method of claim 1 wherein the firstsubstrate comprises a semiconductor substrate.
 3. The method of claim 1wherein the two parallel conductor lines and the one perpendicularconductor line comprise the same conductor material.
 4. The method ofclaim 1 wherein the two parallel conductor lines and the oneperpendicular conductor line comprise different conductor materials. 5.The method of claim 1 wherein the two parallel conductor lines and theone perpendicular conductor line comprise a conductor material selectedfrom the group consisting of aluminum, copper and tungsten conductormaterials.
 6. The method of claim 1 wherein said laminating comprises athermal and pressure assisted bonding process.
 7. The method of claim 6wherein said bonding process is performed at a temperature from 20 to800 degrees centigrade.
 8. The method of claim 7 wherein said bonding isperformed at a pressure from 1 to 5 atmospheres pressure.
 9. The methodof claim 1 wherein said second substrate is a semiconductor substrate.10. A method for measuring a contact resistance comprising: providing afirst contact resistance test structure comprising: a substrate; atleast two parallel conductor lines having a first separation distance S1located co-planar over the substrate; and at least one perpendicularconductor line having a first linewidth W1 located perpendicular to,non-planar with and contacting the two parallel conductor lines absent avia interposed between the perpendicular conductor line and either ofthe two parallel conductor lines; and measuring a first resistance R1through the first contact resistance test structure by contact to thetwo parallel conductor lines.
 11. The method of claim 10 furthercomprising: providing a second contact resistance test structure thathas a different parallel conductor line separation distance S2 than thefirst contact resistance test structure; and measuring a secondresistance R2 through the second contact resistance test structure bycontact to the parallel conductor lines.
 12. The method of claim 11further comprising: providing a third contact resistance test structurethat has a different perpendicular conductor line linewidth W2 than thefirst contact resistance test structure; and measuring a thirdresistance R3 through the third contact resistance test structure bycontact to the parallel conductor lines.
 13. The method of claim 12further comprising calculating a contact resistance for parallelconductor line contact to the perpendicular conductor layer from thefirst resistance, the second resistance and the third resistance. 14.The method of claim 13 wherein the contact resistance is calculated as:Rc=[R2−R3−(R1−R2)(b−a)/a]/(2nb) where: a=1−S2/S1 b=1−W1/W2 n=number ofperpendicular conductor layers.